1. Field of the Present Invention
The present invention relates to a process of minimizing false alarm for security alarm system having motion sensors, and more particular to further development on a U.S. patent application Ser. No. 09/145,403, filed Sep. 2, 1998, now allowed as U.S. Pat. No. 5,917,409.
2. Description of Related Arts
As introduced in U.S. patent application Ser. No 09/315,934, it is reported that less than 5% of the triggered alarms are caused by actual illegal events. More than 90% of the triggered alarms are false alarms caused by the motion sensors and human misoperations. False alarms are the unsolved troublesome to both the alarm companies and the police resources. The whole country suffers an unreasonable waste of time and police force. Before the policemen arrive at the sense, no one knows that whether it is a false alarm or an actual alarm. Therefore, the local police resource charges the alarm owner for a pretty high amount of false alarm operation fee for each false alarm and most of the users have a lot of compliant about that too. It creates a great burden to the limited police force in every city. In fact, millions expense have been wasted for the police resources in responding the false alarms, that greatly degrades the efficiency and performance of the police. Accordingly, some of the police stations in this country consider abandoning such alarm response service. It will only be good news to all burglars. Therefore, how to effectively minimize the possibility of false alarm becomes an urgent topic to both the alarm users and the police resources.
In U.S. Pat. No. 5,917,409, the applicant successfully suggests a novel process and system for reducing motion-type false alarm of security alarm system, which effectively minimize the possibility of false alarm and substantially prevent the waste of police force as well as the unreasonable false alarm operation fee charged by the police to lo the alarm owner.
In U.S. patent application Ser. No. 09/315,934, the applicant further develops a self-analyzing and self-adjusting process to adjust the duration of the delay period during the verification condition according to the substantial needs, so as to ensure the best security and minimizes the false alarm.
In fact, motion-type false alarms are commonly caused by animal, insect, balloon, temperature, lighting, and other environment effect, etc. According to the recorded statistics data, more than 95% of the motion-type false alarm is caused by "single zone trigger" and less than 5% of the motion-type false alarm is caused by "cross zone trigger", i.e. more than one zones trigger, within a certain period of time such as 10 to 30 minutes. In which, each motion sensor is installed to monitor a respective motion detecting area, i.e. a security zone such as a room in a building. The "single zone trigger" of the security alarm occurs when the same motion sensor located in a respective security zone detects two or more activities within a predetermined period of time. The "cross zone trigger" of the security alarm occurs when two or more motion sensors located in different security zones detect two or more activities respectively within a predetermined period of time.
In other words, if more than one motion-type sensors (detectors) which are monitoring different security zones are triggered during the predetermined period of time, such as 10 or 30 minutes, there is a very high possibility, more than 95%, that it is caused by intruder breaking in or human activities occurred through different security zones.
On the other hand, it is a well known headache that despite the new features, motion sensors based solely on PIR technology and "single zone" operation still reach hard limits in the balance between catch performance and false alarm immunity.